Pump for fluids containing solids



Oct. 24, 1961 G. Nl-:IDL

PUMP FOR mums CONTAINING soLIDs Filed March 3l, 1958 3,005,597 PUMP FURFLUmS CONTAINING SOLIDS Georg Neidl, 108 Schonfliesser Strasse, Berlin-Frohnau, Germany Filed Mar. 31, 1958, Ser. No. 725,141 Claims priority,application Germany Apr. 11, 1957 1i) Claims. (Cl. 241-255) Thisinvention relates to a pump for uids containing solids, and moreparticularly to a rotary pump for the conveyance of fluids, such aseffluents, thick pulps and the like.

Rotary pumps for the conveyance of effluents, thick pulps and the likeare known, in which the pump body is made in the form of a disc arrangedat an inclination to the shaft axis and rotating within a stationarycasing, the supply branch being positioned in the axis of the casing,while the delivery branch lies at the periphery of the casing. Accordingto a further proposal teeth, serrations or similar protuberances areprovided at the periphery of the pump body with the object of exerting atearing eiTect on impurities, more especially textiles, which arecarried along by the lluid to be conveyed.

.By this means it was intended to prevent any clogging of the pump.

It has been found, however, that these known pumps do not always fullysatisfy the requirements, more particularly, where it is a problem ofdealing with highly resistant impurities, such as chemical libres.According to the invention, particularly good results are obtained, byforming the pump body as a disc fixed obliquely to the shaft in its axisand providing it at the same periphery with teeth, serrations,projections or depressions in such a manner that these teeth and thelike engage in grooves provided in the internal surface of the pumpcasing. The disc preferably is of an elliptical form,

such that the clearance between the teeth, serrations, projections ordepressions at the outer periphery of the disc and the grooves at theinner periphery of the pump casing is the same at all points and in allpositions of the disc. This clearance may also be kept slight and evenreduced in certain circumstances to such an extent that the ellipticaldisc with its teeth, serrations, projections and depressions is insubstantial contact all over in the cylindrical pump casing, so there isno longer any clearance.

For technical reasons of manufacture and for reasons of simple floatingassembly it may be of advantage to provide the groove-like depressionsin the inner surface of a two-part, axially divided bushing which isinserted axially into the one-piece pump casing. The disc may be madewith a plane surface or be spatially curved or, a pump body of any otherform may be used, which must be such, however, that at least portions ofthe pump body will perform tumbler or wobbling motions and that theperipheral parts are provided with teeth, serrations, projections orrecesses, which engage in corresponding grooves at the periphery of thecasing.

Finally, it may be of advantage to cut away the elliptical disc at bothnarrow sides in such manner with respect to the disc surface that eachcut surface after the disc body has been mounted in the pump casing, isat the same distance with respect to the inner surfaces of the twocasing covers in all positions of the pump over the whole surface.

lThis formation of the disc body possesses on the one hand technicalmanufacturing advantages, in that the teeth, etc. need only be carriedout as far as these side surfaces. For, should the teeth, etc. in thecase of a pure ellipse be carried out right up to the main axis of theellipse, diiiiculties would be experienced, as the tooth profile wouldhave to be given a shape no longer l arent capable of being carried out,while, on the other hand, the cutting away of the ellipse at the twonarrow sides has the advantage, that the pump disc can be mounted notonly against the inner end surface of the two casing covers, but can beallowed to run round, so that should this clearance be made very smallor even allowed to drop to zero-tight, jointing between the cut awaysurfaces of the pump body and the inner surfaces of the casing covers isbrought about.

This may be of special importance, when eiiluents are to be conveyed,which contain considerable accumulations of textiles, more particularlychemical fibres. Such an eiiluent is drawn in by suction through theinow branch into the pump in the case of a pump disc supported in afloating or overhang inclined manner on the side facing away from theshaft. The rags contained in the eiliuent will then be thoroughly tornapart and ground up between the teeth of the pump body and the groovesof the pump casing, whereupon they will together with the water beconveyed away through the outflow branch.

The tight jointing between the cut away inclined surfaces and the innerend surfaces of the casing cover has the advantage, that no larger partsof the rags will pass into that space in the interior of the casing, inwhich the shaft is contained. This is of importance for the reason, thatthese rags would wrap themselves'round the shaft and thereby choke thepump.

Instead of a single disc, a plurality of discs may be provided which aremounted obliquely to the pump shaft on the latter, and which areprovided with projections, depressions or proles and engage incorresponding grooves at the inner periphery of the casing or of thecasing bushing.

The invention is illustrated yby the constructional examples in theaccompanying drawings, in which:

FIGURE l is a view in elevation and partly in crosssection of a pumpembodying the present invention;

FIGURE 2 a partial axial section on a larger scale through the pump atthe location, where the disc teeth engage in the grooves of the pumpcasing,

FIGURE 3 is an elevational view showing the pump body removed from thepump and clamped in the expending chuck of a lathe, for illustrating theproduction of the toothing,

FIGURE 4 shows another constructional form of the pump in axial sectionwith a spatially curved pump disc,

FIGURE 5 shows yet another constructional form of the pump in axialsection with two pump discs crossing one another,

FIGURE 6 shows another constructional form of the pump in axial sectionwith segment-like cut away parts at the two narrow sides of theelliptical pump body,

FIGURE 7 a plan view of the disc-shaped pump body of FIGURE 6, and

FIGURE 8 is a modification of teeth and groove arrangement of FIGURE 2.

According to the constructional form of FIGURES 1 to 3, a pump shaft 1is floatingly supported in a bearing 2 and is provided wit-h a stuffingbox 3. To enlarged end 4 of the pump shaft, the above-described pumpdisc 5 is fixed obliquely by means of counter-sunk screws, so that thesurface of the pump disc 5 remains smooth and nothing can adherethereto. At the outer periphery of the pump disc 5, teeth 6 are cut byturning, and which teeth engage in grooves 7 of Vserrated or otherwisedepressed proiile. These grooves are cut at the inner periphery of abushing 8 which is pushed into cylindrical casing 9 and lixed with itsflange 10 by screws 11 to flange 12 of the casing 9. At the innerperiphery, the bushing 8 is provided with a cut away area 13 which opensinto a corresponding recess in the casing 9, which recess communicateswith a delivery branch 14. An

Y v inlet branch 15 is connected by means of a flange 16 with the flange12 of the casing 9.

The disc which is of elliptical shape, when viewed perpendicularly inthe direction of the arrow A is so formed as an ellipse that, afterbeing mounted in the pump, it appears circular, in the axial projectionthat is in the direction of the arrow B. This disc 5 is so made, asregards its dimensions, that its teeth, serrations, projections ordepressions engage with clearance (compare FIGURE 2) in the grooves 7 ofthe bushing.

Each point of the disc S travels during the rotary mo tion of the discalong circular paths with respect to the Shaft 1, assuming the viewer tobe on the disc 5. On the other hand, each point of the disc 5 performs,when viewed from the casing inlet, not only rotary motions, but alsooscillatory motions. It follows, that during the rotary motion of thedisc 5, a certain thrust effect towards the left and right will beexerted within the casing 9, which, however, is greatly exceeded by thecentrifugal force of the fluid to be conveyed, so that the conveyedmaterial enters from the inlet'branch 15 into the casing, being forcedout through the delivery branch 14.

From the relative points of view of the aforesaid observer, assuming himto be on the disc 5 or on the casing 9, it follows, that the grooves 7do not lie helically in the bushing 8, but are arranged concentricallyto one another.

For illustrating the motions, it should be pointed out, that in FIGUREl, the disc 5 is shown in plan view. Assuming, however, that the disc 5is turned out of the position of FIGURE 1 through 90, according to thedirection of rotation backwards or forwards Vit would be seen, that thedisc 5 will then appear in FIGURE l with groove within the bushing 8 ofthe pump, the cutting Ytool 21 is brought into the position shown bydotted a twisted surface, so that the disc will, as it were, shovel theconveyed material out of the pump towards theA delivery branch 1-4.

Through the thrust referred to above Ycertain losses may occur, it istrue, should the disc 5, viewed in the direction of the arrow A, be madenot elliptical, but circular, in which case the disc, viewed in thedirection of the arrow B would appear as an ellipse. These losses wouldbe due to the circumstance, that between the periphery of the discv 5and the inner surface of the casing a substantially greater distancewould be created at thev location of the minor axis of the ellipsethanin the region of its major axis. For ythis reason it will be ofadvantage to make the disc of such a shape that thedistance between itsperiphery and the inner surface of the casing is the same at alllocations. 'Ihis will be brought about through the disc 5 being madeelliptical in the direction of the arrow A in such manner that, viewedin the direction of the arrow B it will appear circular.

For the assembly of the pump it is necessary to make the bushing 8 intwo parts in the axial section, so that, as shown in FIGURE 1, a joint19 is formed. The assembly will then be carried out in the followingmanner: After the shaft has been mounted in the bearing 2 and after thecylindrical Vcasing part 9 has been hanged to the cover 17 on themachine frame 18, the two halves of the bushing 18 are placed outsidethe casing round the disc 5V and the disc together with the two bushinghalves 8 are placed into the casing 9, until the disc 5 'Y strikesagainst the enlarged end 4 of the shaft 1. Thereupon the disc 5 issecured by means of the screws onto the enlarged end 4 of the shaft 1. Y

The screws 11 of the bushing 8 are then tightened and, finally, theinlet branch 15 is screwed to the lian-ge r12, of the casing.

For producing the teeth for the disc 5, the shaft 1 of the pump with thesecured disc 5 is clamped in jaws 20 of the chuck of a lathe (FIGURE 3)Yand by means of a tool 2,1, the profile of which corresponds to the gapbetween the teeth to be produced, starting at one end of the disc, thefirst teeth with corresponding profile is cut.

Thereupon, corresponding to the distance apart of the 75 34.

Y 15 (FIGURE l).

' pump body having blading or other profiling,

lines in FIGURE 3 and, by bringing the tool to bear the second toothdepression is cut in at two oppositely ydisposed places into the disc.In this way the tool 21 is displaced step by step over the whole widthof the disc, whereby the latter is provided with teeth over the entireperiphery, which are so formed that after being mounted in the casing,they will engage in the corresponding -grooves of the bushing 8.

The advantage of the present invention consists in giving the disc anelliptical shape for the purpose of avoiding unnecessary lateral thrustsand turbulences, and in effectively shutting off the end of the shaft 1which projects into the casing, with respect to the inlet branch This isdue to the fact that the teeth 6 of the disc S are in engagement duringthe rotary motions permanently with the grooves 7 of the bushing 8, sothat the textile impurities entering through the inlet branch 15 intothe left hand part of the casing with the efuent can never enter thoseparts of the casing in which there is a portion of the shaft, withoutthese textile pieces not having been previously iinally shredded by theteeth 46 of the disc. This tine tearing up is produced lmainly by thecutter-like coaction of the teeth 6 with the grooves 7. Hence, thewrapping of textiles round the pump shaft, which is frequently observedin the case of the known pumps and necessarily leads to the jamming ofthe pump, can never occur.

Nevertheless, the side of the disc, shown to the 'right in FIGURE 1,also operates with a shovel action. Assuming the disc 5 to be turnedthrough 180 with respect to the position shown in FIGURE 1 (seedash-line representation), it will be seen at once, that the deliverybranch 14 is now in communication with the right hand side of the disc,that is to say, this half of the casing as well will ll up with conveyedmaterial which will be shovelled towards the ydelivery branch 14.

It is of advantage, even if not absolutely necessary, to leave someclearance between the groove 7 of the casing bushing, which istooth-Shaped in cross-section, and the disc teeth 6, to ensure softrunning of the pump. Tests have shown, that the teeth of the discsatisfactorily tear up and disintegrate the rags and textiles within thegrooves 7, even when there is clearance. In many cases it is even foundto be of advantage to have a considerable clearance between the teeth 6and 7, more particularly, for instance, when slices of sugar beet are tobe pumped, where an all too great disintegration is not desirable.

In a modified form of the invention, disc 22 may be made arcuate (as inFIGURE 4). For the rest, however, the disc is made elliptical at itsperiphery in such a manner that, viewed in the direction of the arrow C,the periphery Vof the disc is circular, so that the disc teeth willengage in the grooves of the casing bushing. According to theconstructional lform of FIGURE 5 two discs 23 which cross and penetrateone another can be fixed obliquely on the pump shaft. Each disc hasperipheral teeth which engage in the grooves of the casing bushing.

The pump bodies may have continuous archings or depressions, havingraised places in themselves or the it being only of importance, that theperipheral parts of the pump body shall engage in the teeth in theinterior of the casing. Finally, the pump body may be provided withperforanons, in order to reduce the thrust, which is of specialadvantage in the case of semi fluid conveyed materials.

According to the constructional form of FIGURES 6 and 7 the pump disc 24is cut away at both narrow sldes 29, so that plane section surfaces 30are formed. These section surfaces 36 are so placed with respect to thesurface of the pump body disc 24 that they extend parallel to the innersurfaces 31, 32 of the two casing covers 33, YAS Will be ,Seen fromFIGURE 6, there is clearance between the surfaces 30, 31 and 36, 32namely a clearance 35. If required, this clearance may be brought downto zero, so that a more or less good tight jointing between the surface36 and the inner surfaces 31, 32 of the covers 33, 34 of the pump casingis ensured.

This tight jointing has the advantage, that, in the case or waterheavily permeated with rags, which penetrates through the inlet branch44 into the material of the pump, these rags are extensively torn up bythe teeth of the disc body and the grooves in the interior of thecasing, without the possibility of larger pieces of rag getting intothat part of the casing, which contains the shaft 43, so that there isalso no danger of rags becoming wrapped round this shaft.

The area 36 shown white in FTGURE 6 shows the open-l. ing in thebushing, through which the fluid passes into the delivery branch shownat the top.

According to the invention it is necessary to so arrange the disc 24 atan angle to the pump shaft 43 that the two section services at thenarrow sides 29 of the disc 24 will be directed to the inner surfaces31, 32 of the two casing covers 33, 34. Only in this case is the cuttingaway of the pump disc 24 at the two narrow sides 29 of any use. If thedisc 24 were to be placed at a considerably steeper angie to the shaft43, the two section surfaces 30 would not be directed to the innersurfaces 31, 32 of the two casing covers 33, 35:, but directly to thegrooved bushing 45. ln that case the disc would not actually be cutaway, but have to be formed in the direction A of FIGURE l as a fullellipse and be provided with teeth right up to the ends of the majorellipse axis.

The angle of inclination between the disc 24 and the shaft axis 43should preferably be made such that the left hand section 30 of thedisc, as will be seen in FIGURE 6, as it were encircles the internaldiameter of the suction branch 44, without entering this internaldiameter. Otherwise, the conveyed material entering the pump through thesuction branch would irnpinge on the section surface 30 of the disc 24,which would be of disadvantage. Through the choice of a denite angle ofinclination, as described above, a favourable efficiency of the machineis also obtained.

According to the invention, the teeth 6 may also be formed that theywill not end in a point to the outside, but will appear flattened off atthe upper ends in accordance with illustration of FIGURE 2, thus nolonger having cutting edges which are sharp at the top. Analogously, thegrooves 7 are, as shown in FIGURE 2, not made triangular incross-section, but have the form of a section through a trapezoidalthread. Of course, not screwthreads, but only parallel grooves are cutin the bushing 8.

This kind of formation of the teeth and grooves has the great advantagefrom the manufacturing point of View, in that the pump disc 5 canreadily be made together with the teeth 6 and the bush 8 with thegrooves 7 by casting rather than by turning. Subsequent tooling willthen be entirely superfluous, when a suitable amount of clearance isleft more particularly between the teeth 6 and the grooves 7. In spiteof this the tearing effect is hmdly reduced at all, because the teeth,viewed in opposition to the direction of rotation, operate with theirfront edge and not with their cutter-like points'.

I claim:

1. A rotary pump for conveying fluids such as effluents,

thick pulps and like materials, comprising a cylindrical casing havingan inlet and an outlet for the material being conveyed, a shaftextending at least partially into the CII casing concentric to the axisof the casing, a pump body supported by the shaft obliquely to the axisof the shaft, said pump body being defined as an elliptical disc havingperipheral teeth-like components along at least two edges thereof, andthe inner peripheryof the cylindrical casing being provided with groovesof corresponding axial section with which said teeth-like projections ofthe disc cooperate so that on rotation of the shaft a combined rotaryand oscillatory movement is imparted to the elliptical disc to scoop thematerial entering the inlet to the outlet while the teeth-likecomponents and grooves coact to disintegrate any solid matter in thematerial, thereby preventing such matter from engaging and imparing theArotation of the shaft.

2. A rotary pump as claimed in claim 1, in which the teeth-likecomponents of the disc and the grooves of the casing are so formed as toprovide a clearance between such teeth-like components and groove.

3. A rotary pump as claimed in claim 1, in which said grooves areprovided in a two-part bushing insertable axially into the casing.

4. A rotary pump as claimed in claim 1, in which said pump body isdefined as a spatially curved disc.

5. A rotary pump as claimed in claim 1, in which the narrow sides ofsaid disc are formed as plane surfaces and said casing is provided withend walls having plane faces whereby during rotation of the pump bodythe same degree of clearance exists betwen the plane surfaces of thedisc and the plane faces of the end walls in each position of the pumpbody during rotation.

6. A rotary pump as claimed in claim 5, in which the plane surfaces ofthe di-sc extend parallel to the plane faces of the end walls.

7. A rotary pump as claimed in claim 5, in which the clearance betweenthe plane surfaces of the disc and the plane faces of the end walls isreduced to zero.

8. A rotary pump as claimed in claim l, further including at least oneadditional elliptical disc arranged perpendicularly to the rst-mentioneddisc.

9. A rotary pump as claimed in claim 1, in which said grooves arearranged concentrically to one another.

10. A rotary pump as claimed in claim 1, in which the angle between theelliptical disc and the shaft is so selected that the peripheral portionof the disc facing the inlet during rotation of the disc describes acircle, said circle being greater than the inlet opening discharginginto the casing.

vReferences Cited in the file of this patent UNITED STATES PATENTS489,723 Titus Ian. 10, 1893 1,131,230 Giddings Mar. 9, 1915 1,697,202Nagle Jan. l, 1929 1,980,589 Acree Nov. 13, 1934 2,336,798 Nash Dec. 14,1943 2,501,275 Heller Mar. 2l, 1950 2,610,836 Clarke Sept. 16, 19522,718,012 Howe Sept. 20, 1955 FOREIGN PATENTS 19,579 Australia of 1934183,980 Austria Dec. l0, 1955- 240,004 Germany Oct. 25, 1911 501,662Germany July 5, 1930 819,346 Germany Oct. 31, 1951 932,556 Germany Sept.5, 1955

